266406661 has 2 divisors, whose sum is σ = 266406662. Its totient is φ = 266406660.

The previous prime is 266406659. The next prime is 266406667. The reversal of 266406661 is 166604662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 228584161 + 37822500 = 15119^2 + 6150^2 .

It is a cyclic number.

It is not a de Polignac number, because 266406661 - 2¹ = 266406659 is a prime.

Together with 266406659, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 266406661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (266406667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133203330 + 133203331.

It is an arithmetic number, because the mean of its divisors is an integer number (133203331).

Almost surely, 2^266406661 is an apocalyptic number.

It is an amenable number.

266406661 is a deficient number, since it is larger than the sum of its proper divisors (1).

266406661 is an equidigital number, since it uses as much as digits as its factorization.

266406661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 37.

The square root of 266406661 is about 16321.9686618986. The cubic root of 266406661 is about 643.4503277848.

The spelling of 266406661 in words is "two hundred sixty-six million, four hundred six thousand, six hundred sixty-one".